灵芝多糖对小鼠T细胞胞浆游离Ca2+浓度和胞内pH的影响

目的通过考察灵芝多糖(GLP)对免疫细胞信号转导过程的影响,探讨GLP免疫调节作用机制。方法采用激光扫描共聚焦显微镜(LSCM)技术,动态监测GLP均一体组分GLB7对小鼠T细胞胞浆游离Ca     

灵芝多糖对小鼠T细胞胞浆游离Ca~(2+)浓度和胞内pH的影响

目的通过考察灵芝多糖（ＧＬＰ）对免疫细胞信号转导过程的影响,探讨ＧＬＰ免疫调节作用机制。方法采用激光扫描共聚焦显微镜（ＬＳＣＭ）技术,动态监测ＧＬＰ均一体组分ＧＬＢ７对小鼠Ｔ细胞胞浆游离Ｃａ２＋浓度（［Ｃａ２＋）和胞内 ｐＨ（［ｐＨ］ｉ）的影响。结果 ＧＬＢ７（２０ｍｇ·Ｌ－１）引起小鼠 Ｔ细胞中［Ｃａ２＋］;和［ｐＨ］;明显升高,１ｍｉｎ即分别升高至３３４．７０％±１６,４％（ｎ＝３）、１７１．６％ ± １０．４％（ｎ＝３）,之后一直分别维持在该平台期,至 １０ ｍｉｎ仍维持高峰水平。加入ＥＣＴＡ和 ｖｅｒａｐａｍｉｌ处理后, １０ ｍｉｎ ＧＬＢ７ 引起 Ｔ细胞［Ｃａ２＋］;和［ｐＨ］;分别升高为 ２０２．４％± １３．６％（ｎ＝３）。１４０．２％±７．８％（ｎ＝３）,与正常对照组比较差异有显著性（Ｐ＜０．０1）。以 ＥＧＴＡ和 ｖｅｒａｐａｍｉｌ处理后,再分别以 ｈｅｐ－ｅｒｉｎ和 ｐrocaine处理细胞 １０ ｍｉｎ,之后以 ＧＬＢ７刺激Ｔ细胞,１０ｍｉｎ［Ｃａ２＋］ｉ值分别为１５１．５％±９．４％（ｎ＝３）、１４３．２％± ８．１ ％（ ｎ＝ ３）,与 ＥＧＴＡ和 ｖｅｒａｐａｍｉｌ处理组相比差异有显著性（ Ｐ＜ ０．０１）。同时以     

Differential effects of 20 non-dioxin-like PCBs on basal and depolarization-evoked intracellular calcium levels in PC12 cells

Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) are environmental pollutants that are well known for their neurotoxic effects. Numerous in vitro studies reported PCB-induced increases in the basal intracellular calcium concentration ([Ca(2+)](i)), and in vivo NDL-PCB neurotoxicity appears at least partly mediated by these disturbances. However, effects of NDL-PCBs on depolarization-evoked calcium influx are poorly investigated, and effects of several congeners, including PCB53, on calcium homeostasis are still unknown. We therefore studied the effects of 20 selected NDL-PCBs on basal and depolarization-evoked [Ca(2+)](i) in fura-2-loaded PC12 cells using single-cell fluorescence microscopy. The results demonstrate that hexa- and heptachlorobiphenyls (with the exception of PCB136) were unable to affect basal and depolarization-evoked [Ca(2+)](i). However, most tri- and tetrachlorinated as well as some pentachlorinated NDL-PCBs (at 1 and 10μM) increased basal [Ca(2+)](i) during a 15-min exposure. The increase in basal [Ca(2+)](i), which differed in kinetics for the different congeners, depended partly on influx of extracellular calcium and calcium release from the endoplasmic reticulum. Importantly, all tested tri- and tetrachlorinated biphenyls and some pentachlorinated NDL-PCBs (PCB95, PCB100, and PCB104) reduced depolarization-evoked [Ca(2+)](i), with PCB51 and PCB53 being most potent (near complete inhibition at 1μM). The reduction in depolarization-evoked calcium influx depended on the exposure duration but not on the foregoing PCB-induced increase in basal [Ca(2+)](i). The inhibition of voltage-gated calcium channels is a novel and sensitive mode of action for NDL-PCBs that contributes to the disturbances in calcium homeostasis and likely is related to NDL-PCB-induced (developmental) neurotoxicity.     

Inhibitory effects of melatonin on free intracellular calcium in mouse brain cells

目的：研究褪黑激素（Ｍｅｌ）对老年小鼠大脑皮层突触体内钙含量以及激动剂诱发的新生小鼠脑细胞［Ｃａ２＋］ｉ升高的影响,以探讨Ｍｅｌ抗衰老的作用机理．方法：钙离子荧光染料Ｆｕｒａ２ＡＭ负载已制备的突触体或细胞,用ＲＦ５０００型双波长荧光分光光度计测定［Ｃａ２＋］ｉ．结果：长期使用Ｍｅｌ抑制老年小鼠大脑皮层Ｃａ２＋超负荷,Ｍｅｌ也降低钙通道激活剂ＢａｙＫ８６４４,高浓度氯化钾（ＫＣｌ）和谷氨酸钠诱发的分离的新生小鼠脑细胞［Ｃａ２＋］ｉ升高．结论：Ｍｅｌ对中枢神经元［Ｃａ２＋］ｉ超载的抑制作用与其抗衰老作用有关．     

褪黑激素对小鼠脑细胞内游离钙浓度的抑制作用

目的 研究褪黑激素（Ｍｅｌ）对老年小鼠大脑皮层突触体内钙含量以及激动剂动诱发的新生小鼠脑细胞（Ｃａ＾２＋）升高的影响,以探讨Ｍｅｌ抗衰老的作用机理。方法 钙离子荧光染料Ｆｕｒａ－２ＡＭ负载已制备的突触体或细胞,ＲＦ－５０００型双波长荧光分光光度计测定（Ｃａ＾２＋）ｉ,结果：长期使用Ｍｅｌ抑制老年小鼠大脑皮层Ｃａ＾２＋超负荷,Ｍｅｌ也降低钙通道激活剂Ｂａｙ－Ｋ８６４４,高浓度氯化钾（ＫＣｌ）和谷氨酸     

Effect of lead and arsenic on murine macrophage response

Splenic macrophages are highly efficient in trapping and concentrating foreign substances carried in the blood and also the major sites where antibodies are synthesised and from where they are released into the circulation. Lead and Arsenic as environmental agents are considered to be high priority toxic substances largely due to their carcinogenic potentials in humans. However, these heavy metals as carcinogens remain an enigma because while they are definitely active in humans, carcinogenesis in the rodent model has never been convincingly demonstrated. Although macrophages are predominantly recruited to the site of inflammation during inflammatory distress as well as in immune response, nothing is known about the interaction of lead and arsenic with macrophages and their possible role in immunotoxicologic effect. In the present study it is reported that in vivo lead acetate treatment (10 mg/kg body wt) inhibits the cell adhesion property and alters the cell morphology in the splenic macrophages. Results show that there is a significant decrease in alkaline phosphatase release in lead treated macrophages (6.7 +/- 0.88 IU/100 mL) with respect to control (14.17 +/- 0.18). In vivo exposure of sodium arsenite (0.5 mg/kg body wt) also decreases phagocytic activity for ingestion and digestion of exogenous antigens, such as whole microorganism, as evident from the phagocytic index, 11555.55 +/- 62.86 (in control) to 5555.5 +/- 1571.33 in arsenic treated cells. Arsenic exposed cells release 8.15 +/- 0.05 microM nitric oxide, whereas control cells release 10.95 +/- 0.15 microM of nitric oxide, which is also identical following LPS stimulation. Results show that the functional integrity of the target cell is also decreased after arsenic exposure as obtained from the percentage of DNA fragmentation. A greater percentage of DNA fragmentation upon arsenic treatment (43.1 +/- 0.05%) with respect to control (14.9 +/- 0.34%) indicates that arsenic induces apoptosis. In immune cells which are rapidly proliferating and differentiating, inhibition of these heavy metal induced functions may result in similar degree of toxicity and lead to diseased state.     

The effects of nitrogen mustards on the proliferative and Ig synthetic response of human peripheral blood lymphocytes

Maximal inhibition of pokeweed mitogen-stimulated Ig production and [3H]thymidine incorporation was shown to occur when unfractionated human peripheral blood mononuclear cells were cultured with concentrations of the nitrogen mustards melphalan, mechlorethamine or chlorambucil in the 20-100-microM range, whereas concentrations of microsome-activated cyclophosphamide (A-Cy) in the 2-mM range were required for equivalent inhibition. Around 400 microM A-Cy, IgM secretion was not inhibited, but secretion of IgA and IgG was. The [3H]thymidine incorporation of enriched populations of both large and small B and T cells all showed about 20-50-fold greater sensitivity to melphalan than to A-Cy, despite a difference of only 6-fold in alkylating activity between these drugs. Large (250 micron 3) B and T cells were only marginally more sensitive to melphalan and A-Cy than small (210 micron 3) T and B cells. Kinetic studies showed that IgG and IgA secreted by day 7 could be maximally inhibited by melphalan added as late as day 3, and IgM synthesis as late as day 2. In contrast, inhibition of Ig production by A-Cy steadily declined after the first day, especially IgM, which was no longer inhibitable by A-Cy on day 3. Inhibition of cumulative Ig production did not occur when A-Cy or melphalan was added on day 5 or later. Cell recombination experiments performed with drug pulsed and untreated monocytes plus B cells and irradiated T cells showed that inhibition of [3H]thymidine or Ig production was most striking when monocytes + B cells (rather than T cells) were exposed to melphalan in the first 16 h. When A-Cy was used in the first 16 h, inhibition of Ig production was partial and inconsistent, and inhibition of monocytes + B cell or T cell [3H]thymidine incorporation was not evident. We conclude that the nitrogen mustards melphalan and A-Cy can inhibit pokeweed mitogen-stimulated DNA synthesis by human T or B cells and Ig production in vitro, but that their mechanisms of action differ.     

Ethanol and platelet intracellular free calcium concentrations.

The effect of 0.8 g kg-1 absolute ethanol orally on platelet intracellular free calcium was assessed in a random order study in 24 normotensive subjects with an isocaloric control. Platelet calcium was measured 90 min and 12 h after treatment by the Quin 2 method. The study had 90% power of detecting a 16.5% change. After 90 min, breath ethanol was 37 +/- 9 micrograms 100 ml-1, blood pressure was unchanged and heart rate rose slightly. Platelet calcium was unchanged by ethanol after 90 min or 12 h.     

槲皮素对血小板聚集和胞浆游离钙的影响(英文)

目的:研究槲皮素对凝血酶诱导的血小板聚集和胞浆游离钙浓度的影响及钙对槲皮素的血小板聚集抑制效应的作用。方法:用荧光钙离子指示剂观察槲皮素对血小板胞浆游离钙的影响.结果:槲皮素明显抑制凝血酶诱导的血小板聚集和游离钙的升高.IC_(50)和95％可信区间分别为146.2(92.4～231.3)和78.5(49.5—124.4)μmol·L~(-1).槲皮素对血小板的抑制作用可被钙翻转.槲皮素对凝血酶诱导的钙释放无影响.结论:抑制钙内流是槲皮素抑制血小板聚集和[Ca~(2 )]_i升高的机制.     

Differential effects of chlorpromazine and chlorpromazine free radical on calcium transport in sarcoplasmic reticulum vesicles

Chlorpromazine activates, and chlorpromazine free radical inhibits, the calcium transport system of fragmented sarcoplasmic reticulum. The associated calcium-dependent ATPase is affected in a similar manner. However, the calcium independent (basal) ATPase is not reduced in activity by the free radical. It is suggested that unmodified chlorpromazine rather than its free radical form is the pharmacologically active moiety.     

Extracellular calcium is required for the polychlorinated biphenyl-induced increase of intracellular free calcium levels in cerebellar granule cell culture.

Recent studies from the laboratory indicate that polychlorinated biphenyl (PCB) congeners can alter signal transduction and calcium homeostasis in neuronal preparations. These effects were more pronounced for the ortho-substituted, non-coplanar congeners, although the mechanisms underlying these effects are not clear. In the present study the time-course and concentration-dependent effects of coplanar and non-coplanar PCBs on intracellular free calcium concentration ([Ca2+]i) in cerebellar granule cell cultures were compared using the fluorescent probe fura-2. The ortho-substituted congeners 2,2'-dichlorobiphenyl (DCB) and 2,2',4,6,6'-pentachlorobiphenyl (PeCB) caused a gradual increase of [Ca2+]i while the non-ortho-substituted congeners 4,4'-DCB and 3,3',4,4',5-PeCB had no effect. The increase of [Ca2+]i produced by 2,2'-DCB was time- and concentration-dependent. Further studies examined possible mechanisms for this rise in [Ca2+]i. In contrast to the muscarinic agonist carbachol, the effects of 2,2'-DCB on [Ca2+]i were not blocked by thapsigargin and required the presence of extracellular calcium. The effects of ortho-substituted PCBs may depend on their ability to inhibit calcium sequestration as 2,2'-DCB significantly inhibited 45Ca2+-uptake by microsomes and mitochondria while 3,3',4,4',5-PeCB had no effect. In addition, 2,2'-DCB significantly increased the binding of [3H]inositol 1,4,5-trisphosphate to receptors on cerebellar microsomes, suggesting another possible mechanism by which ortho-substituted PCBs can mobilize [Ca2+]i. These results show that PCBs increase [Ca2+]i in vitro via a mechanism that requires extracelluar calcium, and support previous structure-activity studies indicating that ortho-substituted PCBs are more potent than non-ortho-substituted PCBs.     

As_2O_3诱导人肝癌细胞凋亡及对Fas表达和钙含量的影响

化疗在原发性肝癌的综合治疗中占重要地位.为寻找肝癌治疗新的有效药物,我们观察了As2O3对人肝癌细胞株BEL7402的生物学效应,以期为As2O3临床治疗肝癌提供实验依据.     

Salmon calcitonin-induced modulation of free intracellular calcium.

Salmon calcitonin (sCT), a hormone shown to modulate calcium in the periphery modulated free, intracellular calcium, ([Ca++]i), in mouse brain synaptosomes as measured by changes in fura-2-mediated fluorescence. A 5-min incubation of synaptosomes with sCT produced an increase in the basal levels of [Ca++]i and an increase in KCl-stimulated levels of [Ca++]i. A 5-min pretreatment of mice with intraventricularly administered sCT antagonized morphine-induced antinociception in the tail-flick test, and facilitated naloxone antagonism of morphine. Conversely, pretreatment of synaptosomes for 1 h with salmon CT produced a decrease in depolarization-stimulated levels of [Ca++]i. The sCT-induced decrease in the stimulated rise in [Ca++]i at 1 h correlated temporally to sCT-induced antinociception in vivo. The effects of sCT in the electrically stimulated guinea pig ileum bioassay appeared to correlate to sCT effects in vivo. The data indicate that calcitonin may function as a neuromodulator via modulation of Ca++ within the central nervous system.     

Differential effects of manoalide on secreted and intracellular phospholipases

Manoalide, a novel nonsteroidal sesterterpenoid, is a potent inhibitor of phospholipase A2 isolated from bee and cobra venoms. This report compares the inhibition by manoalide of phospholipase A2 in crude cytosol fractions from four mammalian tissues with that of four purified extracellular phospholipase A2's. Phospholipase A2 isolated from bee venom (Apis mellifera) was the most sensitive to inactivation by manoalide (IC50 approximately equal to 0.12 microM). Extracellular phospholipase A2 from rattlesnake and cobra venom was intermediate in sensitivity to manoalide (IC50 values of 0.7 and 1.9 microM respectively). Porcine pancreatic phospholipase A2 was relatively resistant to inactivation by manoalide (IC50 approximately equal to 30 microM). The phospholipase A2 assayed in crude cytosol fractions from four mammalian tissues exhibited IC50 values of 30 microM or greater. Cytosolic proteins as well as bovine serum albumin and poly-L-lysine (Mr = 57,000) protected purified bee venom phospholipase A2 from inactivation by manoalide. In contrast, amino acids such as lysine and alanine failed to protect the purified enzyme from inactivation. Proteins and certain amino acids, such as lysine, formed a chromogenic product when incubated with manoalide. These data suggest that lysine is capable of reacting with manoalide, but only when it is present in macromolecules is it capable of protecting phospholipase A2 from inactivation by manoalide. Because cellular proteins protect PLA2 from inactivation by manoalide, high concentrations of manoalide must be applied topically to produce statistically significant inactivation of intracellular phospholipase A2. Finally, a chemical model is presented which explains the formation of a chromogenic product when manoalide is incubated with proteins and amino acids.     

PCP and analogs prevent the proliferative response of T lymphocytes by lowering IL2 production. An effect related to the blockade of mitogen-triggered enhancement of free cytosolic calcium concentration

The psychotomimetic drug PCP displays a vast array of known pharmacological effects, among them its capacity to affect cation transport in nervous and myocardiac tissues. Since increased movements of cations are essential for the immune responses, it has been mentioned that PCP could also depress immune functions by this mechanism. In order to check this hypothesis, we have investigated the effects of PCP and of many other structural derivatives on the blastogenic response of murine or human T lymphocytes. We find that all the drugs block an early event of T lymphocyte activation and prevent their further proliferation; conversely they do not affect primed lymphocytes. The compounds, which do not inhibit interleukin-1 (IL-1) production in stimulated macrophages, lower interleukin-2 (IL-2) synthesis in activated T helper cells. This negative action appears to be related to the inhibition of the rise of free cytosolic calcium concentration [Ca2+]i observed soon after the T receptor triggering and which is an essential message for IL-2 production. The lymphocyte membrane depolarization induced by the drugs could explain the blockade of the lectin-induced [Ca2+]i changes. The study of the structure-activity relationship shows that the PCP analogs which possess a quasi-rigid conformational structure express an inhibitory capacity of T lymphocyte proliferation higher than that of PCP (200 times for some products). Since these compounds interact poorly with the CNS tissues and have few behavioral effects, we suggest that PCP exerts its negative action on lymphocytes on cell components different from its receptor(s) in the CNS.     

Nicotine suppresses the proliferative response of peripheral blood lymphocytes in rats

Nicotine, the psychoactive ingredient of cigarette smoke, alters lymphocyte function in vitro. However, unlike tobacco smoke, the immunologic effects of nicotine in vivo have not been determined. In the present study a single SC administration of 0.33, 0.66, or 1.32 mg/kg (free base) of nicotine bitartrate to male rats produced a dose-dependent decrease in the in vitro proliferative response of blood lymphocytes to the T-cell mitogen Con A when sampled 1 hr after nicotine administration. These results strongly suggest that acute nicotine exposure can induce immune perturbation in vivo. Nicotine also increased plasma corticosterone (CORT) and there was a substantial negative correlation (r = ?.52) between CORT levels and the extent of proliferation (DPM) for the optimal Con A dose. The correlation between nicotine's immunologic and CORT effects is discussed within the context of several other potential mediators of nicotine's effects. © 1992 Wiley-Liss, Inc.     

小胶质细胞内钙离子水平调控机制研究进展

钙离子是细胞内重要的第二信使,参与调控许多细胞和组织的生理活动,包括肌肉收缩、新陈代谢、分泌以及细胞分裂.细胞内的钙信号对小胶质细胞的功能有着广泛而复杂的影响.本文通过对二者之间关系的总结,阐述了钙离子水平在小胶质细胞活化中的作用,为日后进一步研究二者的关系提供方便.